"If I have enough ego to say I'm a writer, a director, a producer, and an actor, I should have the energy and the knowledge to write a scene for this great actor named Henry Fonda and direct him in it and have it work"

This quote by Peter Fonda speaks to the significance of believing in one's capabilities. He is saying that if he has the ego to call himself a writer, director, producer, and actor, then he ought to have the energy and understanding to write a scene for a great actor like Henry Fonda and direct him in it. This suggests that he believes in his own capabilities and that he is positive that he can create something terrific. It also speaks to the significance of having the right knowledge and energy to develop something terrific. It is insufficient to merely have the self-confidence to call oneself an author, director, producer, and actor; one need to also have the understanding and energy to produce something that will work. This quote is a pointer that confidence in one's capabilities is very important, however it is also crucial to have the right understanding and energy to produce something terrific.